Steep (8)
'steep' is the definition.
(I know that steep can be written as expensive)
This is all the clue.
(Other definitions for expensive that I've seen before include "Highly-priced" , "Costing a lot of money" , "High in price" , "Pricey" , "Very costly or dear" .)
'steep' is the definition.
(marinating is a kind of steeping)
This is the entire clue.
(Other definitions for marinate that I've seen before include "Soak meat in a sauce" , "Soak meat, fish etc" , "Soak food in a minaret" , "Pickle" , "Soak food in flavoured liquid before cooking" .)